1. Field of the Invention
This invention pertains to chromogenic panels, such as glass windows, for vehicular and architectural use, and more particularly, to a chromogenic assembly for use in a vehicle's sunroof. In addition, the invention pertains to chromogenic skylights, architectural blocks and window assemblies. Further, the present invention pertains to chromogenic light pipes and chromogenic aircraft windows. The present invention also pertains to boat or other marine application windows.
2. Related Background Art
A variety of technologies exist for producing chromogenic members. "Chromogenic devices", as used herein, is employed as commonly known in the art. Examples of these chromogenic devices include electrochromic devices, photochromic devices, liquid crystal devices, user-controllable-photochromic devices, polymer-dispersed-liquid-crystal devices, and suspended particle devices.
The term "user-controllable" is used in the sense that the appearance of a chromogenic device can be regulated. Photochromic devices, because their coloration is a function of light intensity are not directly "user-controllable". However, systems incorporating such photochromic devices can be designed in which users can regulate such devices. For the purposes of this application, those systems would also be considered "user-controllable".
For example, electrochromic devices are discussed by N. R. Lynam and A. Agrawal in "Automotive Applications of Chromogenic Materials", Large Area Chromogenics: Materials & Devices for Transmittance Control, C. M. Lampert and C. G. Granqvist, Eds., Optical Engineering Press, Bellingham, Wash. (1989), the contents of which are incorporated by reference herein, and by D. V. Varaprasad, H. R. Habibi, N. R. Lynam and P. Desaraju in U.S. Pat. No. 5,142,407, entitled "Method of Reducing Leakage Current in Electrochemichromic Solutions Based Thereon", U.S. Pat. No. 4,793,690, entitled "Rearview Mirror Control Circuit", U.S. Pat. No. 4,799,768, entitled "Automatic Rearview Mirror With Filtered Light Sensors". Other pertinent references include N. R. Lynam, "Electrochromic Automotive Day/Night Mirrors", SAE Technical Paper Series, 87036 (1987); N. R. Lynam, "Smart Windows for Automobiles", SAE Technical Paper Series, 900419 (1990); C. M. Lampert, "Electrochromic Devices and Devices for Energy Efficient Windows", Solar Energy Materials, 11, 1-27 (1984); Japanese Patent Document No. JP 58-20729 (Kamimori); U.S. Pat. No. 3,521,941 (Deb); U.S. Pat. No. 3,807,832 (Castellion); U.S. Pat. No. 4,174,152 (Giglia); U.S. Pat. No. Re. 30,835 (Giglia); U.S. Pat. No. 4,338,000 (Kamimori); U.S. Pat. No. 4,652,090 (Uchikawa); U.S. Pat. No. 4,671,619 (Kamimori); U.S. Pat. No. 4,702,566 (Tukude); U.S. Pat. No. 4,712,879 (Lynam); U.S. Pat. No. 5,066,112 (Lynam) and U.S. Pat. No. 5,076,674 (Lynam), U.S. Pat. No. 5,239,406 (Lynam), U.S. Pat. No. 5,073,012 (Lynam), U.S. Pat. No. 5,122,647 (Lynam) and U.S. Pat. No. 5,148,014 (Lynam, et al.), the contents of each of which are incorporated by reference herein.
Electrochromic panels are also discussed by Sapers, S. P., et al. in "Monolithic Solid-State Electrochromic Coatings for Window Applications", Proceedings of the Society of Vacuum Coaters Conference (1996), with regard to devices of the type shown in FIG. 1E. Devices comparable to that shown in FIG. 1E, and having photovoltaic layers for self-biasing operation are described in U.S. Pat. No. 5,377,037, entitled "Electrochromic-Photovoltaic Film for Light-Sensitive Control of Optical Transmittance".
Other references of interest include U.S. Pat. No. 5,241,411, entitled "Electrochromic Variable Transmission Glazing, U.K. Patent No. 2,268,595, entitled "Electrochromic Cell", Japanese Laid-Open Patent Appln. No. 63-106731, entitled "Dimmer Body", Japanese Laid-Open Patent Appln. No. 63-106730, entitled "Dimmer Body", and U.S. Pat. No. 5,472,643, entitled "Electrochemichromic Sunroof". Also pertinent is PCT Patent Application No. PCT/US 97/05791, entitled "Electrochromic Devices", which pertains to electrochromic devices that can vary the transmission or reflection of electromagnetic radiation by applying an electrical stimulus to an EC device. This is done using a selective ion transport layer in combination with an electrolyte having at least one redox active material to provide a high-performance device.
Photochromic devices are discussed by N. R. Lynam and A. Agrawal in "Automotive Applications of Chromogenic Materials", Large Area Chromogenics: Materials & Devices for Transmittance Control, C. M. Lampert and C. G. Granqvist, Eds., Optical Engineering Press, Bellingham, Wash. (1989).
Also suitable for use in this invention are liquid crystal devices such as those described by N. Basturk and J. Grupp in "Liquid Crystal Guest-Host Devices and Their Use as Light Shutters", Large Area Chromogenics: Materials & Devices for Transmittance Control, C. M. Lampert and C. g. Granqvist, Eds., Optical Engineering Press, Bellingham, Wash. (1989).
User-controllable-photochromic devices (UCPC) are discussed in U.S. Pat. No. 5,604,626, entitled "Novel Photochromic Devices", the contents of which are incorporated by reference herein.
Polymer-dispersed-liquid-crystal (PDLC) devices are described by N. R. Lynam and A. Agrawal, "Automotive Applications of Chromogenic Materials", Large Area Chromogenics: Materials & Devices for Transmittance Control, C. M. Lampert and C. G. Granqvist, Eds., Optical Engineering Press, Bellingham, Wash. (1989).
Suspended particle devices are discussed in U.S. Pat. No. 4,164,365, entitled "Light Valve for Controlling the Transmission of Radiation Comprising a Cell and a Stabilized Liquid Suspension" (Saxe), the contents of which are incorporated by reference herein.
The general control of chromogenic devices is discussed in U.S. Pat. No. 4,793,690, entitled "Rearview Mirror Control Circuit", U.S. Pat. No. 4,799,768, entitled "Automatic Rearview Mirror With Filtered Light Sensors", U.S. Pat. No. 5,007,718, entitled "Electrochromic Elements and Methods of Manufacturing and Driving the Same", and U.S. Pat. No. 5,424,898, entitled "Fault Tolerant Drive Circuit for Electrochromic Mirror System", and the disclosure of those references is incorporated by reference herein.
The phenomenon of prolonged coloration of chromogenic devices is discussed in U.S. Pat. No. 5,076,673, entitled "Prolonged Coloration Electrochromic Assembly", U.S. Pat. No. 5,220,317, entitled "Electrochromic Device Capable of Prolonged Coloration", and U.S. Pat. No. 5,384,578, entitled "Electrochromic Device Capable of Prolonged Coloration". The disclosure of those references is incorporated by reference herein.
FIGS. 1A through 1E depict typical examples of electrochromic devices, while FIGS. 1F through 1H show other types of chromogenic devices.
For example, FIG. 1A depicts a layered EC device which includes a substrate 101, transparent conductor 103, electrochromic (redox) medium 105, transparent conductor 103' and substrate 101'.
FIG. 1B illustrates a layered EC device which includes a substrate 101, transparent conductor 103, EC layer 107, electrolyte (redox medium) 109, transparent conductor 103' and substrate 101'.
FIG. 1C shows another layered EC device having a substrate 101, transparent conductor 103, EC layer 107, ion-selective transport layer 111, electrolyte (redox medium) 109, transparent conductor 103' and substrate 101'.
Still another such EC device is shown in FIG. 1D. This device includes a substrate 101, transparent conductor 103, EC layer 107, electrolyte 113, counterelectrode 115, transparent conductor 103' and substrate 101'.
FIG. 1E shows an EC device having a substrate 101, transparent conductor 103, EC layer 107, electrolyte (ion-conductive layer) 117, counterelectrode 115 and transparent conductor 103'.
A typical liquid crystal or PDLC device is shown in FIG. 1F; this device includes a substrate 201, transparent conductor 203, liquid crystal or PDLC medium 205, transparent conductor 203' and substrate 201'.
Another example of a typical liquid crystal device is depicted in FIG. 1G. The device includes a polarizer 207, substrate 201, transparent conductor 203, alignment layer 209, liquid crystal medium 205, alignment layer 209', transparent conductor 203', substrate 201' and polarizer 207'.
An example of a UCPC device is shown in FIG. 1H, and this device contains a substrate 201, transparent conductor 203, chromogenic layer 211, electrolyte (redox) medium 210, transparent conductor 203', light-sensitive electrode 213 and substrate 201'.
FIG. 1I shows a typical photochromic device. It includes a substrate 301, photochromic medium 303 and substrate 301'.
FIG. 1J shows another typical photochromic device. The device has a substrate 301 and photochromic layer 303.
Yet another typical photochromic device is shown in FIG. 1K; this consists of a photochromic substrate 305.
Since these chromogenic devices are themselves known to those skilled in the art, a detailed explanation of their manner of construction and operation is not believed to be necessary.
Vehicular sunroofs have become an increasingly popular automotive option in recent years. These devices provide the vehicle occupants with a feeling of open-air driving, increase air circulation through the passenger compartment, and add a sporty appearance to the vehicle. The typical automobile sunroof constitutes a glass panel which allows occupants to have an open view through the roof of the vehicle even when the sunroof is itself closed.
While in many ways desirable, sunroofs affect the interior design of automobiles. Many vehicles include, at least as an option, an overhead console for the storage of sunglasses and other items and vehicle accessories such as garage door opening transmitters, overhead lights, and compass displays. Typically, a vehicle with a sunroof has only a relatively small area between the windshield and the forward edge of the sunroof opening for such an overhead console. This space is undesirably small, however, and offers much less room than that is found in the larger overhead consoles available in vehicles without a sunroof.
Glass sunroofs transmit a great deal of heat and light, particularly under sunny conditions or in warm climates. For example, it has been found that the interior temperature of a vehicle parked in the sun for two hours can exceed 167.degree. F. ("Solar Ventilates, Recharges Vehicle", Photonics Spectra, Vol. 25, p. 20 (1991)). This causes overheating of the interior of the vehicle. Such overheating can be a serious problem, because recently-required changes in the types of refrigerants which can be used in automotive air conditioning systems reduce the cooling ability and so cause the vehicles to cool more slowly. Therefore, the flow of heat through the glass portions of the car has become an increasingly important concern for car designers.
High solar light levels also may fill the car with ultraviolet, visible and infrared radiation. Visible radiation causes glare which is undesirable because at the least, it constitutes an annoyance to the occupants. Also, ultraviolet radiation may bleach or discolor the vehicle's interior. The incoming infrared radiation leads to heat buildup with consequent occupant discomfort and deterioration of interior cabin materials.
Chromogenic technology such as electrochromic technology has been described in the prior art as having the potential for application to automotive sunroofs. Many electrochromic systems effectively block the transmission of infrared radiation in their darkened state. Thus, electrochromic elements will effectively prevent solar heat gain in vehicles and will provide the user with dynamic control of the transmissive properties of the glass roof. Sunroof designs may feature glass sunroofs with both electric tilt and slide functions.
In designing a chromogenic sunroof, it may be preferable to integrate the electronics which control the coloring and bleaching of the device with those which control the slide and tilt mechanisms. This would permit greater ease of installation, a more compact unit, and reduce the likelihood of failure.
According to the prior art, chromogenic glass panels, if used for a sunroof, are installed directly in the roof opening. See U.S. Pat. No. 5,261,722, entitled "Variable Opacity, Maximally Transverse Retracting Sunroof System", and U.S. Pat. No. 4,750,816, entitled "Electrochromic Element Comprising an Organic Oxidative Color-Forming Layer and an Inorganic Reductive Color-Forming Layer". One issue of concern in such designs is that the chromogenic elements are exposed to environmental factors such as direct ultraviolet ("UV") light, temperature fluctuations and extremes, rain and dust. Such chromogenic elements also can be struck by debris kicked up on the road, i.e., gravel and rocks, and so could be damaged. In addition, from the standpoint of manufacturing efficiency, economy and customer satisfaction, it is difficult to make chromogenic components having the same shape as existing sunroofs, which have curvatures matching the contours of the vehicles in which the sunroofs are installed. Hence, most chromogenic devices such as laminate-type electrochromic devices involve a construction comprising glass substrates sandwiching a chromogenic medium (such as an electrochromic medium). It is more economical and manufacturable to fabricate flat panels of area larger than about one square foot or thereabout. By sandwiching the chromogenic medium between two flat panels, this obviates the need for precision bending and matching of two curved panels. The term contour as used herein means a non-flat surface, i.e., a curved surface. For example, the outer skin of a vehicle such as the outer skin of the vehicle roof is typically contoured such that it is non-flat and is curved and is frequently of compound and complex curvature (here, "contoured" means "curved"). Furthermore, retrofitting by installing chromogenic panels in existing sunroofs without altering the car appearance is quite complicated. Similar problems would also be encountered with aircraft windows.
Light pipes are frequently used in buildings to harness exterior light and direct the light to the interior of the building. The light may be diffusely delivered. Light pipes are similar to skylights insofar as they both use natural light to brighten a room. However, skylights are often more difficult and expensive to install in a retrofit situation than light pipes.
The main element of a light pipe is a circular tube, typically of metal. The inside surface may be coated with a reflective mirror finish. The tube which is typically 3-6 feet in length and extends through the roof where it is covered by a clear cover, typically an acrylic dome. A small reflector located inside or outside the tube can help direct light down the tube. Inside, the tube ends at the ceiling surface, where it is typically covered with a diffuser that spreads light across the interior area. Since the reflective tubing may be fitted between ceiling joists, thereby avoiding major construction, they represent an inexpensive retrofit option.
The use of light pipes decreases the reliance on other forms of artificial lighting and hence reduces energy bills. However, light pipes have mainly been installed in areas such as hallways and bathrooms, where the presence of very bright light throughout daylight hours is not detrimental. Light pipes could have wider application if there existed a means to selectively darken the light pipe when bright lighting was not desired. Such control of the light output of light pipes can lead to installation of light pipes in other areas such as, for example, bedrooms, conference rooms, theatres, multimedia rooms, multipurpose rooms, and offices.
One method to control the light output of light pipes is to install shades or screens which could be used to cover the light pipe to achieve relative darkness. However this method has several drawbacks such as a narrow selectivity range of brightness intensity, a difficulty in reaching a shade at roof height, and a poor aesthetic appearance.
Such problems with conventional light pipes are addressed by the present invention by providing an electrochromic panel which is fabricated for insertion in a light pipe. The electrochromic panel of the present invention could be selectively darkened to achieve any number of levels of brightness in the room. The panel could be controlled from a wall switch mounted near the unit. These and other advantages will be described in the embodiments described below.
The invention described below addresses all the above issues by providing more flexibility for glazing design, and particularly for automotive glazing, aircraft windows, and interior design. The present invention also provides novel methods and structures for making chromogenic sunroofs as well as other glazing structures for both vehicular and architectural use, such as building skylights, architectural glass blocks, light pipes, car windows, aircraft windows, boat windows, marine applications, and building windows.